A large number of commercial and industrial products comprise aqueous systems containing organic materials. Examples are latexes, surfactants, dispersants, stabilizers, thickeners, adhesives, starches, waxes, proteins, emulsifying agents, detergents, cellulose products, and resins formulated in aqueous solutions, emulsions or suspensions. Such products frequently contain relatively large amounts of water. The temperature at which these products are stored, as well as their pH, makes these products susceptible to the growth of microorganisms. These microorganisms can be introduced during the manufacturing of these products (from exposure to air, tanks, pipes, equipment, and humans), and/or during their use (from multiple openings and reclosures of packaged products, and introduction of contaminated objects to stir or remove material).
Microbiological degradation of aqueous systems containing organic material may manifest itself in a variety of problems. These include loss of viscosity, gas formation, objectionable odors, decreased pH, emulsion breaking, color change, and gelling.
Additionally, aqueous systems, such as cooling water and related water-handling systems, which include cooling towers and associated pumps, heat exchangers, and pipelines, heating systems, gas scrubbing systems and other similar systems commonly encounter problems of corrosion, including the electrochemical corrosion of iron and iron alloys in contact with the circulating water.
For many years, the most common method of controlling corrosion in cooling water and related water-handling systems was to treat the water with hexavalent chromium salts, such as sodium chromate. At the same time, scaling due to slightly soluble calcium salts was prevented by treating the water with mineral acids, such as sulfuric acid, to keep the pH low enough to prevent the precipitation of the scale forming calcium salts. Improvements in this technology over the years included the use of zinc salts and phosphates in combination with the chromates, which could provide good corrosion control at reduced chromate concentrations. However, because of environmental concerns over the discharge of even small amounts of hexavalent chromium in cooling water effluents, new methods continued to be sought that would provide total corrosion inhibition without the use of hexavalent chromium.
Some of the ways that this has been achieved include the use of various combinations of zinc salts, phosphates, polyphosphates, and organic phosphonic acid derivatives and their salts. However, all of these methods in the prior art have certain disadvantages, such as requiring close control of the pH to keep it within a very narrow range or using special additives or dispersants to prevent the precipitation of scale-forming salts like calcium phosphate.
Friedrich et al., Zur Kenntnis des Hexamethylentetramins, I., 54B Berichte 1531-42 (1921), discloses 1-methyl-3,5,7-triaza-1-azoniatricyclodecane compounds which include anions such as methyl sulfate, nitrate, picrate, perchlorate, and thiocyanate groups.
U.S. Pat. Nos. 4,505,831 and 4,650,866 disclose 1-methyl-3,5,7-triaza-1-azoniatricyclodecane compounds, useful as microbicides. These patents, however, are limited to such compounds having halide anions, which are not corrosion inhibiting compounds. U.S. Pat. No. 4,650,866 also discloses a method for preparing such 1-methyl-3,5,7-triaza-1-azoniatricyclodecane halides comprising the reaction of an ammonium halide with methylamine, formaldehyde and ammonia in an aqueous medium.